If you hadn’t already figured that 2012 was going to be a big, big year for tablets, here’s the last piece of evidence you’ll need: Amazon could launch a successor to the original Kindle Fire as soon as next month.

This year, we’ve already seen a Retina Display-packing new iPad and Microsoft’s tandem of tablets, the Surface and Surface Pro. Google’s Nexus 7 tablet is expected to make its debut tomorrow and go on sale in July. Would Amazon really want to wait until the end of the year to introduce a new model? Definitely not.

The Kindle Fire was never really positioned as an iPad killer, but rather as a low-cost iPad alternative. It’s been one of the biggest Android tablet success stories to date, but with a Nexus device looming on the horizon Amazon might now be feeling the crunch. So far, most industry sources have pegged the 8GB Nexus 7 at $199. That’s the same price as the Kindle Fire, but there’s the added attraction of having full access to all the apps and games in Google Play as well as the promise of being first in line for future Android updates. Oh right, there’s also that quad-core Tegra 3 processor and front-facing camera.

No official details have surfaced yet about the Kindle Fire 2, but there’s speculation that Amazon will make at least two tweaks to address customer concerns. First, they’ll add physical volume controls — the on-screen-only approach has been highly criticized. Second, they may offer a microSD slot for storage expansion. That’s something Google probably won’t do on the Nexus 7, since they didn’t build one into the Nexus S or Galaxy Nexus. There’s also talk that Amazon will continue selling the original Kindle Fire at the bargain-basement price of $149.